Hi Infinitelove! smart post as usual.
I don't have a real opinion but I find it interesting to contemplate what you suggest as a concrete possibility. Or something a bit in the middle, where both have the chance to pass long periods on their own, for example travelling. There isn't one way to stay together, the "classic" way is often made heavy by a lot of cliche's that make it untrue. I am together with my boyfriend in a "classic" way (inseparable since the beginning 7 years ago, and now with little kid) and we are very in love, but as our life is all and all very unconventional maybe that was kind of necessary for us, or anyway a lot of sharing was what each of us had always dreamt of, but I don't see why one wouldn't want something different, if the focus is different. I myself would like to pass some time by myself every now and then, when our son is old enough, as there is a part of me still undeveloped, the one that doesn't share.